Here's a real shocker: Teens are better than their parents at using the Internet, and are likely to hide some of their online behaviors from them.

That news comes from a 2,017-person survey funded by the online security software maker McAfee, which is pushing a product that helps parents monitor their kids online.

Seventy percent of teens "hide their online behavior" from parents, according to the report, which was released Monday. That's up from 45% in 2010, the group says.

These hidden behaviors include some things you might expect -- such as accessing violent (43%) or pornographic (32%) content online -- but also a few surprises. Fifteen percent of teens have hacked into social networks; 9% have hacked into e-mail accounts; 12% have met face to face with a person he or she met on the Internet; and 16% of teens surveyed said they had used their phones to cheat on tests at school.

"Parents, you must stay in-the-know," McAfee's Robert Siciliano wrote in a blog post. "Since your teens have grown up in an online world, they may be more online savvy than their parents, but you can't give up. You must challenge yourselves to become familiar with the complexities of the teen online universe and stay educated on the various devices your teens are using to go online.

"As a parent of two young girls, I proactively participate in their online activities and talk to them about the 'rules of the road' for the Internet. I'm hoping that this report opens the eyes of parents to become more involved and also consider using technology such as McAfee Safe Eyes to protect their kids online."

There's the product pitch. McAfee Safe Eyes, like similar products from other security companies, lets parents spy on their kids' online behaviors and block certain websites. According to an online description of the product, Safe Eyes lets parents log the social-media posts and instant message conversations of their children.

[Update: the pitch for McAfee Safe Eyes has since been removed from the blog post.]

Nearly half of parents install some sort of online controls, the survey said. Forty-four percent know their teens' passwords, and one in 10 uses a location-monitoring device.

Not everyone advocates that approach to teen online security, however.

"We don't think it's a good idea for parents to spy on their kids surreptitiously, because eventually they're going to find something they have to confront them about, and it's going to destroy the other lines of communication," Justin Patchin, a criminal justice professor and co-director of the Cyberbullying Research Center, told CNN in 2010.

In the report, McAfee also encourages parents to be upfront with their children if they decide to monitor their behaviors.

"Half of teens say they would think twice about their online activities if they knew parents were watching," the report said.

The McAfee-funded report, which was carried out by the research company TRU, surveyed 1,013 parents and 1,004 teens between the ages of 13 and 17. The interviews were conducted online in May.